The present invention relates generally to 3-D vision systems, and more particularly to a vision system utilizing a laser range scanner which intelligently scans an object based upon images received from a CCD camera.
Passive vision systems, such as CCD cameras, acquire images of the object by sensing the ambient light reflected from the object. These systems require well-defined features such as targets or edges. Further, the quality of the information gathered by the CCD camera is affected by the ambient lighting conditions.
Active vision systems typically utilize a range-scanning laser and therefore do not depend upon ambient light. The laser range scanner obtains object coordinates from external information such as scanning angles, time of flight, or shape of projected patterns. However, the accuracy of the laser range scanner drops when measurements are performed on objects with sharp discontinuities, such as edges and holes. This can be overcome somewhat by increasing the resolution of the laser range scanner; however, increasing the resolution of the laser range scanner over the entire object increases the size of the computer data file to unmanageable dimensions. Increasing the size of the data file also increases the amount of processing needed to generate a computer model. Further, because only a small minority of the area of the object contains the sharp discontinuities, most of the additional data gathered by increasing resolution does not provide useful information about the shape of the object.